imgdv 1.3.5 © 2003-2013 by Turku PET Centre
Estimation of distribution volume (Vt) or distribution volume ratio (DVR)
from dynamic PET images in ECAT 6.3, 7.x, NIfTI-1, or Analyze 7.5 format,
applying model independent graphical analysis approach of Logan et al
[1, 2, 3] for reversible tracer uptake or binding.
Simple non-iterative perpendicular line fitting algorithm [4] is applied
in determination of the slope of the Logan plot.
Parameters:
1) Input file (Plasma or Reference region TAC; times in minutes)
2) Dynamic image file
3) Linear fit start time (0 for automatic determination)
4) Parametric image file
Options:
-k2=<k2 of reference region>
With reference region input it may be necessary to specify also the
population average for reference region k2 [2]
-Thr=<threshold%>
Pixels with AUC less than (threshold/100 x max AUC) are set to zero.
Default is 0 %
-max=<Max value>
Upper limit for Vt or DVR values; by default set pixel-wise
to 10x the AUC ratio.
-min=<Min value>
Lower limit for Vt or DVR values; 0 by default.
-F Remove parametric pixel values that are over 4x higher than
their closest neighbours.
-E=<Fit end time (min)>
Never use data after fit end time.
-V=<filename>
Y axis intercepts times -1 are written as an image in specified file.
-N=<filename>
Numbers of selected plot data points are written as an image.
-h or --help
Print this message and exit.
-v, --version or --build
Print software build information and exit.
--silent
Program works silently, printing only error and warning messages.
--verbose
Program prints more information about what it is doing.
Example:
imgdv ua3818ap.kbq ua3818dy1.v 20 ua3818dv.v
The unit of pixel values in the parametric Vt image is
(mL plasma)/(mL tissue), and DVR images are unitless.
In theory, DVR equals BP+1, and therefore a binding potential image can
be computed from DVR image by subtraction of unity, e.g. using program
ecatcalc. However, this may lead to a large number of pixels with negative
values that may hamper the further statistical or visual analysis.
References:
1. Logan J, Fowler JS, Volkow ND, Wolf AP, Dewey SL, Schlyer DJ,
MacGregor RR, Hitzemann R, Bendriem B, Gatley SJ, Christman DR.
Graphical analysis of reversible radioligand binding from time-activity
measurements applied to [N-11C-methyl]-(-)-cocaine PET studies in human
subjects. J Cereb Blood Flow Metab 1990; 10: 740-747.
2. Logan J, Fowler JS, Volkow ND, Wang GJ, Ding YS, Alexoff DL.
Distribution volume ratios without blood sampling from graphical
analysis of PET data. J Cereb Blood Flow Metab. 1996; 16: 834-840.
3. Logan J. Graphical analysis of PET data applied to reversible and
irreversible tracers. Nucl Med Biol 2000; 27:661-670.
4. Varga J & Szabo Z. Modified regression model for the Logan plot.
J Cereb Blood Flow Metab 2002; 22:240-244.
See also:
imgbfbp,
imglhdv,
ecat2tif,
logan
Keywords: image, modelling, distribution volume
This program comes with ABSOLUTELY NO WARRANTY. This is free software, and
you are welcome to redistribute it under GNU General Public License.